Train-control system



Nov. 19, 1929, w. HOWE 1,736,729

TRAIN CONTROL SYSTEM Fil ed March 12; 1927 gTToRNEY Patented Nov. 19, 1929 UNEZTEE STATES PATENT QJFFEQE W'IN'IHEOP K. HOWE, OF ROCHESTER, NEVJ YORK, ASSIGNOR T0 GENERAL RAILWAY SIGNAL COMPANY, OF ROCHESTER, NEW YORK TRAIN-CONTROL SYSTEM Application filed March 12, 1927. Serial No. 174,831.

This invention relates in general to a train e02 trol system, and has more particular reference to an automatic inductive train control system of the alternating current type, including acknowledging and reset means.

in train control systems of the type referred to, it is usual to have spaced trackway inductors controlled in accordance with the traffic conditions and arranged to inductively influence a normally energized, alternatcurrent, car-carried receiver, to cause such receirer to produce a train restricting influence, such as a brake application, or the like, unless prevented by the proper operation of an acki'iowledging device. It the train restricting influence be exerted it is then generally necessary to manually operate a reset device to re tore the various parts to normal. In such systems the car-carried device usually comprises a main relay, with its energizing circuit tuned to oscillate most freely at the frequency oi? the current employed, so that after being ole-energized, if its armature has assumed its retracted position, the energizing circuit is thereby detuned, and removal of the trackway influence does not result in attraction oi" the armature of such relay, it being necessary, in some independent manner, to restore the arr ature to attracted position. It is well recognized, of course, that movement of a relatirely large mass oi iron, such as an armature, will exert a large eiiect on the tn an of an associated circuit.

lVith the above and other considerations in mind, it is proposed, in accordance with this invention, to provide acknowledging and reset means for respectively preventing, for a temporary period, the dropaway of the main relay armature, upon de-energization of such ay, and for restoring the dropped awa armature to attracted position.

More specifically, it is proposed to provide an electric-magnet associated with the armature of the main relay to exert an attraction thereon when energized, and to have manually operable acknowledging and reset contactors operable to respectively energize the electro-mao net through a circuit including a current limiting resistance, and through a circuit not including the current limiting re sistance, whereby, when energized by the ac lrnowledging contactor, the electro-magnet can hold the relay armature in attracted position but cannot move it to such position, and when energized bv the reset contactor it can move the armature from retracted to attract ed position and hold it so.

Further objects, purposes, and characteristic features, of the present invention will appear as the description progresses, reference being had to the accompanying drawing, showing, solely by way of illustration, and in wholly diagrammatic manner, one physical form which the invention can assume.

The single figure of drawing shows one embodiment oi the present invention as appliec to a simplified type of train control system. I

Referring to the drawing, a stretch of track constituted by rails 1, is divided into blocks by insulating joints 2, and furnished with wayside signals 3, shown as of the semaphore type, but which may equally well be of any other desired type it being deemed unnecessary to show and describe the various signal control circuits and devices. Each signal 3 is arranged to control a trackway inductor 4, at the entrance to its block in such a manner as to place the inductor in active condition un der danger and caution conditions of the block in question, and to place the inductor in inactive condition under clear conditions of such block. The particular means for effecting this control has not been shown or described in detail, as it is deemed quite unnecessary tor a full and complete understanding of the present invention, such control means being well understood by those versed in this particular art.

A receiver 5, shown in the form of an H,

and having two primary coils P, and two as for example, 360 cycles per second. The condenser 7 is so chosen as to tune its circuit to oscillate most freely at the frequency of the current employed.

The secondary coils S are likewise connected in series with each other, with a condenser 10, and coils 11 carried on a core 12 constitutin a main relay MB. The circuit including the condenser 10 is likewise tuned to the frequency of the current employed, and is energized inductively by the transformer acion between the primary and secondary coils on the receiver 5, as is well understood by those versed in this particular art.

The main relay MR has an armature 18, pivoted at 14, and biased to its retracted posi tion by a spring 15, a projection 16 being carried by, and insulated from, the armature 18.

When the receiver passes over an inductor 4, in active condition, the inductor so affects the receiver as to change the distribution of flu threading the secondary coils S, so as to reduce the current flowing in the main relay coils 11, to zero, or at least sufficiently to deenergize such relay and permit the armature 13 to be rocked clockwise by spring 15.

In the event the inductor under consideration be inactive it can exert no appreciable influence on the receiver 5, and the main relay MR remains energized.

Carried by the projection 16 are two contact fingers 16 arranged to control the energizing circuit for a brake applying device EPV which canbe of any usual or desired character, but is here shown as a normally energized electro-pneumatic device arranged when ale-energized to either apply the brakes, or impose any other desired restriction on train movement. The energizing circuit for EPV is traceable from the positive side of generator 28, contact finger 20 and front point of Res, contact finger 24 and front point A070, lower contact finger 16 and front points of MR, the winding of EPV, upper contact finger 16 and front points of MR, back to the negative side of generator 28.

Arranged adjacent the armature projection 16, is an electro-magnet 17, which when energized exerts an attracting influence on the armature 13 to either maintain it in attracted position, or to move it to, and retain it in, attracted position, depending upon the character of energization thereof.

The system also includes a reset device, Res, comprisinga rod 18, manually operable to move contact fingers19 and 20 to control various connections, as explained below. This reset device is arranged to be operable only when the train is stationary, as by being placed in a position accessible only from the ground, in order to avoid operation thereof during movement of the train.

An acknowledging device A070 is shown, and comprises a spring biased, manually operable, rod 21 arranged to operate contact fingers 22, 23 and 24, the finger 24 having a retarded opening effect, due to springs 25 and a dash pot or the like 26. Included in a circuit completed by the acknowledging device, is a current limiting resistance 27.

The source of energy for the electromagnet 17 is shown as a direct current generator 28 directly connected to the alternator 8.

The operation of the system above described is as follows. Assuming that the receiver 5 passes inductively over the inductor 4 when the latter is in its inactive condition, no disturbing influence is exerted on the main relay MR and the parts remain in their normal position as shown, that is, in the position and condition. eXisting during travel under clear conditions.

Assuming now that the car is proceeding into a caution or danger block, under which conditions the inductor 4 in question is in its active condition, this inductor will so influence the receiver 5 as to tie-energize coils 11 and thus cause a dropaway of armature 13 of main relay MB. This will de-energize the brake device LPV at the contact fingers 16 and front contacts of the main relay and produce an automatic brake application, as explained above, the EPV device being normally energized from the source 28 through the circuit traced above, including contact fingers 16 and front contacts of relay MR, and contact fingers 24 and 20 and front contacts of Ads and Res respectively.

The above brake application was incurred under the assumption that the engineman did not operate the aclmowledging device A076. In order to relieve the train from the brake application, and allow it to proceed, it is necessary to restore main relay armature 13 to attracted position in order to reenergize EPV. As explained above, the circuit including coils ll of the main relay, is a tuned circuit, which has its inductive reactance materially decreased, and becomes detuned, by the dropping away of the armature 13, and hence the induced current flowing through these coils is insufficient when the circuit is detuned, to pick up the armature 13. In these circumstances, it is necessary to bring the car to a' full stop in order that the reset device Res can be depressed to thereby energize the electro-magnet 17 through a circuit including contact finger 20 and back contact of Res, generator 28, and contact finger 19 and back contacts of Res, whereupon armature 13 is attracted to its restored position after which it is retained in such position by the induced current flowing in the now tuned circuit including coils 11. It will be noted that the normal energizing circuit for EPV passes through contact finger 20 and front contact of Res so that it is necessary before the train proceeds, to restore the reset device to its normal shown position. This feature of the re.- set device also insures against misuse of the same, as for example, by tying it down in an attempt to avoid a brake application on passing an active inductor without acknowledging.

Under the assumed conditions, namely passage of the receiver 5 over an active inductor i, if the engineman is alert and depresses the lever 21 of the acknowledging device A010, shortly before passing over the inductor, an energizing circuit is completed for the electro-magnet 17 which includes contact finger 22 and back contact of A070, source 28, contact finger 23 and back contact of A070, and the limiting resistance 27. Due to the circuit just traced, including the limiting resistance 27, sufiicient current flows to maintain armature 13 in attracted position, but insufficient current flows from the electro-magnet 17 to move the armature 13 to its attracted position if it has previously dropped away. This prevents the acknowledging device trom being used in a reset capacity. With the armature 13 maintained in attracted position, the deenergization of coils 11 does not cause any break in the energizing circuit for EPV, and an automatic brake application is avoided.

Should the engineman attempt to defeat the purpose of the system in question, by holdin down the acknowledging contactor for too long a time, or depressing it at too early a time, contact finger 24 will nevertheless open after about 15 seconds from the op eration of the acknowledging device, to thereby break the normal energizing circuit for EPV at such contact finger and cause an automatic brake application.

By the system described above it will be seen that the acknowledging device is protected against misuse by having its energizing circuit for the electro-magnet 17, include the current limiting resistance 27. On the other hand, the reset device R68 is positioned to protect it against misuse and is arranged to control an energizing circuit for the eleclJIOJliiigl'lGl? 17 which excludes any limiting resistance whereby to permit it to function to move the armature of the main relay from retracted to attracted position.

In order to more certainly guard against false operation of the system due to crossed wires and the like, double breaks have been provided, that is, a break in both the positive and the negative wire, in the energizing circuits for the brake applying device EPV,

as at the two contact fingers 16 and in the circuits completed by the acknowledging and reset contactors A071: and Res, as at contact lingers 22 and 23, and contact fingers 19 and 20 respectively. In these circumstances, a single cross, as for example, a cross connecting the two wires leading to the lower contact finger 16 cannot operate to close a circnit such, for example, as the normal EPV circuit, when it should be open, as would possibly be the case if the circuits referred to claim 1. In a train control system, a normally energized alternating current car carried ele ment controlled in accordance with traific conditions, an electric brake applying device normally energized to hold off the brakes and controlled by the said element, and means to only temporarily suspend the control between the element and device and only when said element is energized including a manually controlled electro-magnetic means having an energizing circuit including a current lineiting means.

2. In a train control system, a normally energized alternating current car-carried element controlled in accordance with trailic conditions, a brake applying device controlled by said element, means to temporarily suspend the control between the element and device including electro-magnetic means manually energizable through current limiting means, and means to suspend the control (for an indefinite period including manually operable means to energize the electro-magnetic means through a circuit shunting said current limiting means.

3. In an alternating current train control system, an influence receiving device normally energized through a tuned circuit, a normally energized electric brake control means initiated upon deenergization to set the brakes and energized through a circuit controlled by said device, and means for only temporarily preventing de-energization of the brake control means by the influence re ceiving device including a manually controlled member having an energizing circuit including a current limiting means acting to allow said preventing only if the receiving device is not already deenergized.

l. In an alternating current train control system, an influence receiving device normally energized through a tuned circuit, a brake control means initiated upon de-energization and energized through a circuit controlled by said device, means for temporarily preventing de-energization of the brake control means by the influence receiving device including a member energized through a circuit including a current limiting means, and means for re-energizing the brake control means including a manually operable device for energizing said member through a circuit excluding said current limiting means.

5. In a train control system, a car-carried relay normally energized by alternating current and controlled in accordance with traffic conditions, a normally energized brake device initiated upon de-energization and having an energizing circuit including a front contact of the relay, and an electromagnetic device, manually energizable, to respectively prevent de-energization of, and to re-ener gize, the brake device, through a circuit including a current limiting means, and a circuit excluding such current limiting means.

6. In a train control system, a car-carried relay normally energized by alternating current and controlled in accordance with traffic conditions, a normally energized brake device initiated upon de-energization and having an energizing circuit including a front contact of the relay, an electro-magnet, acknowledging means to energize the magnet to hold up but not pick up, the said relay, and reset means to energize the magnet to pick up and hold up the said relay.

7. In a train control system, a carcarried relay normally energized by alternating current and controlled in accordance with trafiic conditions, a normally energized brake device initiated upon de-energization, and having an energizing circuit including afront contact of the relay, an electro-magnet, acknowL edging means to energize the magnet, through a current limiting resistance, to hold up but not pick up, the said relay, and reset means to energize the magnet, through a circuit excluding said resistance, to pick up the said relay.

8. In a train control system, a main control relay subject to trackway influences, a brake control device normally controlled by the relay, a second device associated with the relay and affecting the control of the brake control device by the main relay, and separately c0ntrollable energizing circuits including separate manually operable switches, for the said second device permitting different amounts of current to flow through said second device to thereby vary the manner in which said second device can affect said control.

9. In a train control system,a main control relay subject to trackway influences, a brake control device normally controlled by the relay, an electro-magnetic device associated with the relay, and two manually controlled energizing circuits for the said device permitting different amounts of current to flow through the device causing, respectively, hold up only, and pick up and hold up, currents to flow through the electro-magnetic device.

10. In a train control system, a main control relay subject to trackway influences, a brake control device normally controlled by the relay, a device associated with the relay,

ground, to energize the device with sufficient.

current to pick up the armature of the control relay.

11. In a train control system, anormally energized main relay controlled in accordance with traffic conditions, a tuned energizing circuit for said relay detuned on release of the relay armature, a brake applying device controlled by said relay, a coil associated with the main relay for respectively holding up, and picking up, the main relay armature, an acknowledging energizing circuit for said coil including a current limiting member for energizing the coil to be effective to hold up but not to pick up the main relay armature, and a reset energizing circuit for said coil shunted around said current limiting member for en ergizing the coil to pick up the armature of said main relay.

In testimony whereof I affix my signature.

WVINTHROP K. I-IOWVE. 

